D.C. Mun. Regs. tit. 25-D, § 700
700.1 A plumbing system and hoses conveying water shall be constructed and repaired with approved materials according to the International Plumbing Code (2006 edition) or most recent edition, Title 12F of the District of Columbia Municipal Regulations, and the District’s 2008 Supplements, hereinafter referred to as the “Plumbing Code”.
700.2 A water filter shall be made of safe materials.
Source: Final Rulemaking published at 56 DCR 7975 (October 9, 2009).